Piston-packing.



PATENTED AUG. 16, 1904. M. M. BA

PISTON PA G.

. N 0 M 0 D E L.

UNITED STATES Patented August 16, 1904.

MERRIOK M. BARNES, OF BOSTON, MASSACHUSETTS.

PISTON-PACKING.

SPECIFICATION forming part of Letters Patent No. 767,728, dated August 16, 1904.

Application filed February 17, 1902. Serial No. 94,376. (No model.)

To (LU whom it may concern:

Be it known that I, MERRIOK M. BARNES, a citizen of the United States. and a resident of Boston, in the county of Sufi'olk and State of Massachusetts, have invented certain new and useful Improvements in Piston-Packing, of which the following is a specification.

My invention relates to improvements in piston-packing; and its object is to produce a packing adapted especially to pack pistons working under high steam or other pressure.

In the drawings I have shown at Figure 1 in section a portion of the piston-head, which may be of any ordinary construction and to which my improvement is applied. In Fig. 2 I have shown in similar section a modified form of my improved device.

It will be understood that my improvement may be used in connection with the ordinary piston either with or without the bull-ring and follower, the novelty of the invention lying in the construction and arrangement of the packing-ring and its coacting devices.

Many forms of packing-rings heretofore in use have been expressly designed to increase the force with which the packing-ring is pressed against the cylinder-wall under a given working pressure in the cylinder, and a wellknown means for accomplishing this result is the use of a wedge operated either by spring or cylinder pressure, or both, to increase the force with which the packing-ring is pressed outwardly. On the other hand, it-has long been recognized by those familiar with the manufacture and use of piston-ring packing that when working under high pressures say up to two hundred pounds or above-if the packing-ring is allowed to be pressed too tightly against the cylinder-wall it will produce excessive friction, wear out very rapidly, and also produce undue wear of the cylinder itself. My present invention is designed to provide a packing ring or rings especially adapted for use under high pressure and so designed that by means of wedge action the amount of outward pressure of the packingring against the cylinder-wall can be diminished with respect to the working pressure,

while at the same time insuring a tight joint and a long and even wear of the parts. To this end, I provide upon the rear wall of the packing-ring A, which may be of any suitable form adapted to be pressed outwardlyby cylinder-pressure, a bevel or taper, and in connection with this ring I provide what I call a restraining-ring B. This is a ring placed in contact with the packing-ring A, preferably on the side away from the pressure and having its wall which is in contact with the tapered wall of the packing-ring correspondingly beveled or tapered, as shown. In the form of the device shown in Fig. 1 two packing-rings A A are shown and also two restraining-rings B B, each pair being located in a groove in the bull-ring C.

By reason of the wedge construction of the parts A B it will be seen that an original pressure-tight fit of the packing against the bullring O and follower D can be obtained by lightly driving the ring B inwardly or toward thecenter of the piston. If now the device be put in use, it will be seen that the outward force of pressure upon the ring A will be restrained or in part be overcome by the pressure with which outward movement of this ring tends to force the ring B against the side .of the groove in the bull-ring, so that the ring A will press against the cylinder-wall with less than cylinder-pressure. By varying the angle'of bevel of the two adjacent faces of the packing-ring and restraining-ring it will be seen that the force with which the packing-ring is pressed outwardly and against the cylinder-wall may be varied with reference to the cylinder-pressure, thus insuring smooth running and long wear, while at the same time insuring a tight joint between the packing and the piston.

In the modified form shown in Fig. 2 I employ two packing-rings A A, but only one restraining-ring B, which ring has each of its faces adjacent to one of the packing-rings correspondingly beveled. A restraining-ring so constructed acting as a double wedge serves to press and hold both packing-rings tightly against the walls of the groove in the piston-head or bull-ring and also to decrease the force With which each packing-ring is pressed out as cylinder-pressure is applied to it.

5 1 claim The combination with a piston, of a packingring, movable outwardly under cylinder-pressure, and an outwardly-movable ring in beveled engagement With said packing-ring and 10 in frictional engagement with said piston,

whereby the pressure of said packing-ring against the cylinder-Wall is lessened.

. In testimony whereof I have hereunto subscribed my name this 15th day of February, 1902.

MERRICK M. BARNES.

Witnesses:

CHARLES C. KUR'rz, ALEX. P. BROWNE. 

